MEXICO CITY, Oct 22 (Reuters) - Grupo Televisa, Mexico's dominant broadcaster, said on Thursday its third-quarter net profit quadrupled to 3.35 billion pesos ($152 million) from the year-ago period.

Revenue for the quarter ended Sept. 30 totaled 23.9 billion pesos, down about 7% over the same period, largely due to less advertising, it said in a statement.

Televisa's profit surged mostly due to its financial revenue, which reached 3.18 billion pesos during the quarter.

Televisa's audience grew 30% year-on-year for its main broadcast channel during the period, it added.

($1 = 22.1050 pesos at end-September)

(Reporting by David Alire Garcia and Noe Torres, Editing by Daina Beth Solomon and Richard Chang)